"subject to jurisdiction" does not mean "has to follow US law", that is territorial jurisdiction. Subject to jurisdiction means political jurisdiction and allegiance. That is why children born to members of Native American tribes (no matter the location of birth) were considered not subject to jurisdiction because the parents held allegiance to their tribe. Read United States v. Wong Kim Ark (1898).

I don't have an opinion on the legally correct answer, reading the full decision and dissents I'd give a slight edge to the majority.

Where does it say "jurisdiction" only refers to criminal law? Diplomats aren't excluded from being subject to civil laws for "commercial activities," and U.S. courts have jurisdiction over diplomats in suits pertaining to such activities.

You are correct, but you will never sway the account you are replying to. Check their comment history.

They put a ton of effort into carrying water for conservative causes, even when there is no legal or logical backing for them. Just like the conservatives on the supreme court, they arrive at their desired results first and work backward to their justification.